Paper Title
Optimization Inventory Of Crude Oil Lifting Achievement Using Mixed Integer Nonlinear Programming At Pt Pertamina Hulu Energi Offshore Northwest Java (PT.PHE ONWJ)

Abstract
Achievement of realization of crude oil lifting achievement by KontraktorKontrakKerjaSama (K3S) must be achieved to the maximum and optimal because it is very important in supporting the achievement of Indonesia's oil lifting, so that the maximum and optimal achievement will increase revenue for the company and the State. Utilization from internal resources like production rate from wells and capacity to make optimization from crude oil lifting. The research objective is minimizing ending inventory, manage deadstock, and forecasting lifting more accurate. Crude oil is a multiphase flow and has characteristic non-linear properties. Research model using mixed integer nonlinear programming for minimizing inventory stock in Floating Storage & Offloading (FSO) Arco Ardjuna.Mixed integer nonlinear programming making modelling long term period (one year) and short-term period (2-4 weeks). Mixed integer nonlinear programming using excel solver to make spreadsheet material balance inventory. Mixed integer nonlinear programming has objective function minimize ending inventory, for constraint function is capacity limitation, weather, tanker availability, production rate. Result this research successful minimize inventory with technique mixed integer nonlinear programming and sensitivity from wind speed, total production, lifting cost, and tanker availability. Keywords - Crude Oil, Lifting, Inventory, Mixed Integer Nonlinear, Excel Solver.